Microstepping Jumpers

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Erin RobotGrrl

Sep 10, 2020, 3:20:15 PM9/10/20
to Thor: OpenSource 3D printable Robotic Arm

Hi Thor community!

I'm looking through the documentation, and it isn't clear to me if we're supposed to add the microstepping jumpers in.

That is, the jumpers for P1 - P8 that are underneath the stepper drivers. I see on the A4988 datasheet that having all 3 jumpers would be 1/16th step, and it looks like there's defaults in grbl that can change accordingly.

Any clarity on if the jumpers should or should not be added would be appreciated!


Angel LM

Nov 30, 2020, 4:53:02 PM11/30/20
to Thor: OpenSource 3D printable Robotic Arm
Hi Erin,

Sorry for the late reply! Each stepper driver has 3 legs named "MS1", "MS2" and "MS3". Each of those legs is conected to a pin in the ControlPCB. Jumpers connect "MS" legs to "HIGH" level signal (5V). So, having the 3 jumpers connected means to have a 1/16th configuration (this image ilustrates all the possible configurations). My recommendation is to connect all pins to get a 1/16th configuration, but if you want a different one you have to put the jumpers and modify grbl according to the new configuration.

Hope it helps!
Ángel L.M.
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